Large Scale Central

REGEARING THE K-27

General Discussion
#41

The last few days have been spent making and buying additional tooling to make it easier to make these gearboxes.
Still waiting for a order of bearings that I need.
My test loco’s are as follows:
All with the gearboxes. The 1st and 4th drivers have been bushed for no lateral play.
#464 All wiring has been gutted in the loco and tender. 4.2 AH Ni-MH 24V battery, Airwire and Phoenix P=5
8 lbs of lead added and balanced between 2nd and 3rd driver.
#463 Cut stock PC board out of the tender and used B-man wiring. Loco is factory stock 4.2 AH Ni-MH 18V battery,
Airwire and Phoenix P5. 3 lbs of lead added and balanced
#453 Factory stock with a Aristo Rev board installed. 4.2 Ah Ni-MH 18V battery
All loco are wired for trailing car battery.

Gearbox in loco #463 has over 100 hrs of running on it. with the sound off you can here a little gear noise
when it pulling a grade with 2 AMS gons with 25 lbs of lead in them. On the flat and down hill, no noise.
With a 14.2 V battery and the throttle wide open on level track pulling 15 lbs in the gons, 50 seconds to
go 80 feet. Up 2% grade pulling the gons, 200 feet it took 2 minutes 6 seconds.

With this gearing, The loco stays a pretty much a constance speed on the flat in curves and on the grade.
pulling 5 AMS boxcars and a caboose.

#464 will pull 5 gons with over 100 lbs in them on the level track and 70 lbs up the 4% grade. will do some
more weight pulling with #464 and see how well a stock loco will pull on the 4% grade.

I ran #453 with my Accucraft K-28 and they ran very good together.

Rodney

#42

Rodney, can I suggest that you include the appropriate bushes in the kit to fit on the 1st and 4th axles please?

#43

Rodney,

Your latest report sounds great! That is a lot of weight to be pulling up a 4% grade and I’m glad to hear that the noise has diminished. Very exciting news.

John Lyans

#44

Tony
I,ll send you 2 sets with you gearbox.

It’s amazing how well built these engines are built. #453 has over 1000 hours on it and I was worried
about the drivers when I noticed the plating had come off. B-man made the drivers out of a bronze
type material, possibly bearing bronze, and I see no wear on them now. Mechanically, I would rate
it as one of the best plastic loco you can buy. The drive rods have bearing bronze bushings, the worm
in their gearbox looks like stainless steel, the worm gear is of bearing bronze and the other 2 gears
are brass. The valve gear does not show any wear on it that I can see. The only real fault I see is
the gear ratio and the few minor little details that we all know about.

Other modifications I’ve made to my loco are:
1/4 inch shorter draw bar
Ballbearings on the axle shafts of the tenders with plastic trucks (#464, #463)
Loc-tite on all the counterweights and the screws that holds the rods on.
Stiffer driver springs on # 464
Replaced the headlights with 14V bulbs
Replaced the classification lights to 12V bulbs
Magnets on rear driver for the chuff pickup.

Rodney

#45

Here is a update on the gearbox. I redesigned the gearbox again. with the last type I built, I could free wheel the engine forward but in reverse. Also the engine when in reverse would make a lot less noise. This was telling me that there was a bind and most likely it was the way I was doing the thrust bearings. In the earlier design, I had the thrust bearings locked on either side of the outer most output shaft bearing. In the latest design I lock the thrust bearings between the the two bearings of the output shaft. The worm that B-man uses is very aggressive and must use the thrust bearings. Now the engine will free wheel in either forward and reverse and make a lot less noise. With the new design the box is 1/4" longer and interferes with the fan. On the earlier run of the K, I modified the fan cutting the 2 rear posts off the boiler shell and turned the fan over with it still attached the the plastic strip as shown here. Once remounted I cut the long screws that hold the fan to the plastic strip with a Dremal tool with a cut off disk. [url=http://img39.imageshack.us/i/1006529a.jpg/]

(http://img39.imageshack.us/img39/3664/1006529a.jpg)

[/url] With the later released engine I simply unscrewed the fan and turned it over. With this new gear ratio, the fan in my opinion is not needed for cooling the motor. My Berlyn’s and Accucraft’s loco use this same motor and they do not have fans. You will also notice that I do not have the flywheel installed. There is enough room for it, but have the chance of rubbing on the bundle of wires so I leave it off. I have tried a engine with and without it and see no difference. Here is a video of #453 running with the sound off. http://www.youtube.com/watch?v=ELVN922w6HY Rodney

#46

The fan in the pic is the wrong way around. The printed label needs to face upwards.
However, the advantage of having the fan in the correct way around is, it will ssuck air up from underneath past the motor for cooling, and blow copious quantities of smoke out of the stack.
I see no reason why it cannot be left out if needs be.

Edit Note.
I had to add an s to suck as the program rejects suck. I guess you just have to ssuck it and see. :stuck_out_tongue:

#47

Tony
If the label is suppose to face upwards, then all my fans were installed right
from B-man
As you say the only reason to keep the fan is for the to blow smoke.
Rodney

#48

Rodney.
The fan operates like an airscrew. If it is a Sunon brand fan the frame of the fan usually has an arrow indicating the direction of the airflow. I think you will find that will be towards the label side. The arrow should point towards the top.
Turn on the power and feel which way the breeze blows to be absolutely certain.

Anyway. It is good to hear that Bachmann got some of them put in correctly.

#49

Tony
I went ahead and pulled it out anyway cause I do not use the smoke.

UPDATE
I sent out 12 gearboxes this week and we will start getting some feedback soon.
Some more will go out this week as I get the motors. I have logged more
than 100 hours of running on #463 pulling a 2 gons with #50 of lead this week.
The whinnying noise is still there. I ordered some more Delrin to make the smaller
gear and see if it helps with the noise. If it helps with the noise I will have to do
some testing to see if it will hold up. In the law of gears the the gear that drives should
be made out of stronger material that the driven gear. Most gears in our model
world is made of either Delrin or Acetal so I think it will work.

Rodney

#50

The original reason for the fan was to cool the motor. That’s why the factory installation took no notice of smoke production.

Greg

#51

I put the motor with Rodney’s gearbox in my K-27 last night and was able to run it for about 30 minutes today. The speed is MUCH better. I think that he has it set up at a near perfect gear ratio. At 18 volts it moved along at what seemed like a scale 35-40 mph and it crept along nicely at lower voltage. If Bachmann had set up the K-27 with this gear ratio we wouldn’t be having this discussion. The gearbox seems very robust and sturdy. I wasn’t able to test it pulling a large load going uphill because of rain but I feel confident it will have better torque at low speeds.

The noise is not too bad but there is definitely a vibration/growl/un-smooth sound, (hard to describe), that is more noticeable at low speeds. It seemed to be more noticeable on a left curving track. I intend to test it more on Tuesday when I can clear more of my mainline of the mud and pine needles from the recent rains.

I think that Rodney is really on to something good with this gearbox and I applaud his efforts to keep tweaking it. If it were a little smoother/quieter, I think it would be a perfect solution.

John Lyans

#52

I might have to buy a K-27 just to install that beautiful work!

#53

I have installed one of rodney’s gearboxes in my K. I am running QSI with a 14.8 LiIon battery. The loco is a total rewire and I don’t have any axels bushed, yet. Loco has no extra weight added. I sent my motor to Rodney and he sent me my motor and abox geared for the 14.8 volts with extremely quick turnaround time. What I have found so far: The craftsmanship looks great. The install is straight forward and only requires basic tools. The only problem i had was on my end. TAKE NOTE: the bushings on the drive axle have a key fitting on each bushing that the gear box cover fits onto, if you turn the cover over you can see the rectangluar cut. I didn’t realize this and had a heck of a time installing the cover. Once I realized my mistake it went like a breeze. In performance, the loco has great bottom end. I was holding the coupler doing a generic draw bar test, this loco is a brute! Acceleration is nice and steady. The top end would appear to be half of what it used to be. Even with a 14.8v battery the loco was waaaaay fast, the gear box has slowed it to a much more accurate speed. The gear box does have some noise to it but I have yet to install the loco body back on the chassis so I would assume it will quiet down. Although, the QSI sound does cover it up unless you put your ear right up to it. My layout is still buried in leaves so all of this was done inside on a short 14’ test track. As soon as I get it cleared I’ll give a report from outside, but so far I am very pleased!

#54

I sent my motor off to Rod yesterday. Looking forward to getting it back. At the same time, I’m going to gut the wiring and install a Revo unit. Anyone replaced the optical chuff sensors with anything, or should I just use magnets on an axle?

#55

I did mine the old school way–magnets on a tender axle.

#56

I just ended up using magnets on the #4 driver axle. I kept most of the wiring in the locomotive itself intact, except I had to bypass the front headlight after a static electricity discharge between my finger and the drive rods somehow managed to zap the circuit. (Don’t ask me how…) For the chuff, I just isolated the wires that go to the optical chuff trigger, cut them short, and soldered a magnetic reed switch across, mounting it near the rear axle. Then I took some two-sided tape (the thin stuff, not the foam stuff), and wrapped around the rear axle to form a sticky track onto which I could stick the magnets. Once the magnets were in place, I took some scotch tape cut into a thin strip and wrapped it around the axle. This stuck nicely to the 2-sided tape and over the magnets, holding them in place. No glue, and removable if need be.

In the tender, I gutted everything to wire to the Revolution and Sierra sound. I also cut the retaining clip on the two plugs between the loco and tender. I’ve found they stay in very nicely without them, and are infinitely easier to remove when taking the locomotive in after a run.

Later,

K

#57

Got the Delrin today and will cut some gears this weekend for the small gear.
If the noise is better and the Delrin hold up, then I think I’ll have met the goal
of what I was after.
Again THANKS to you guys that are helping me.

Kevin,
I also use magnets on the 4th axle but I have them glued and 2 have come off.
I will try your tape method. Sounds easy and simple. I like your idea of cutting
off the tabs also. Thanks for the tips.
I’m waiting for some more bearings and when they get here, your gearbox will
be in the mail.

Terry

Thanks for the update.

Rodney

#58

Today I installed Rodney’s gearbox between the factory Pittman motor and the existing Bachmann gearbox. It sure works well now; what a huge improvement. At full voltage, (19 volts), the engine moves along at just over a half of it’s original speed. At 14 volts, (the voltage I intend to use to RC/battery control), the speed is much more realistic with way better torque. It will pull 10 cars up a curving 4% grade barely slowing. It’s more like starting up in 1st gear instead of 3rd gear. Before the conversion the engine would slow way down on even modest curves and then would take off like a rocket on the straight track. Now only minor voltage changes are needed if at all. I have been testing a gearbox for Rodney and the only issue I encountered was having a set screw on the worm that was interfering with the gear. This was making a noise as I noted in an earlier post. The set screw needed to be shortened by about a millimeter. Now it is very smooth and quiet. I uploaded a video to Youtube from my phone. The noise you can hear is from a plane that I didn’t notice while I was shooting the clip

http://www.youtube.com/watch?v=bGENcVgSbv0

Rodney is ready to start installing these now. Right now he is having people send him the motor and he is installing the box on their motor. I think most anyone could do the install themselves but it does require some type of gear puller to pull the worm from the motor shaft and some type of press to put it on the new output shaft. Rodney is setting up a website to sell these and some other cool products as well. His URL is:

http://www.randkrailroadproducts.com/

I know that Rodney has been working on this project for two years and I am really happy to have a solution for the gear ratio problem. This brings the ratio close to what I think Bachmann originally intended. My K-27 may finally start to log some mileage.

John Lyans

#59

Got the gear box installed in mine this morning. Couldn’t run it since I’m still waiting on the RC gear from Don Sweet, but I did hook up a transformer to it to test it out. Rod warned me about the flywheel and the wiring, so I did basically what B’mann had done, only I used electrical tape and a small tie wrap.

(http://rgsgardenrailroad.com/K_regeared01.jpg)

(http://rgsgardenrailroad.com/K_regeared04.jpg)

It was surprisingly simple to do. Now all I have to do while the boiler is off is replace those red marker lights on the front end. I found the marker lights were pretty easy to take apart to get to the LED’s inside.

#60

Got mine in the mail today and dropped it in place. A nifty piece of engineering.

Ken, are you going to gut all those electronic boards?